Abstract

We present a semiconductor saturable absorber mirror (SESAM) mode-locked thin-disk laser generating 80 μJ of pulse energy without additional amplification. This laser oscillator operates at a repetition rate of 3.03 MHz and delivers up to 242 W of average output power with a pulse duration of 1.07 ps, resulting in an output peak power of 66 MW. In order to minimize the parasitic nonlinearity of the air inside the laser cavity, the oscillator was operated in a vacuum environment. To start and stabilize soliton mode locking, we used an optimized high-damage threshold, low-loss SESAM. With this new milestone result, we have successfully scaled the pulse energy of ultrafast laser oscillators to a new performance regime and can predict that pulse energies of several hundreds of microjoules will become possible in the near future. Such lasers are interesting for both industrial and scientific applications, for example for precise micromachining and attosecond science.

Figures (5)

Evolution of the maximum pulse energy available from mode-locked thin-disk oscillators since their first demonstration in the year 2000. The result presented in this Letter is highlighted with a red star symbol.

Nonlinear reflectivity of the SESAM used for the high-energy TDL and corresponding least-squares fit. The operation fluence of this SESAM at the maximum output pulse energy of our high-energy TDL is marked in red.

Top: Autocorrelation (left) and optical spectrum (right) of the pulses and corresponding sech2 fits. Middle: RF spectrum with a 16 MHz span and a RBW of 30 kHz (left) and with a 60 kHz span with a RBW of 1 kHz (right). Bottom: Sampling oscilloscope trace (left) and M2 measurement performed using a commercially available scanning-slit automatized beam profiler and a focal length of f=100mm (right). All data was taken at the maximum pulse energy of 80 μJ.